Datasheet AD8367 (Analog Devices)

500 MHz, Linear-in-dB VGA with AGC Detector AD8367 FEATURES FUNCTIONAL BLOCK DIAGRAM Broad-range analog variable gain: −2.5 dB to +42.5 dB VPSI VPSO ENBL 3 dB cutoff frequency of 500 MHz 12 11 2 ICOM AD8367 1 14 ICOM Gain up and gain down modes INPT 3 9-STAGE ATTENUATOR BY 5dB BIAS 9 DECL Linear-in-dB, scaled 20 mV/dB 13 Resistive ground referenced input HPFL gm 10 Nominal Z VOUT CELLS IN = 200 Ω On-chip, square-law detector SQUARE Single-supply operation: 2.7 V to 5.5 V GAUSSIAN INTERPOLATOR LAW DETECTOR ICOM 7 8 OCOM APPLICATIONS 4 5 6
001
MODE GAIN DETO Cellular base stations
02710-
Broadband access
Figure 1.
Power amplifier control loops Complete, linear IF AGC amplifiers High speed data I/O GENERAL DESCRIPTION
The AD8367 is a high performance 45 dB variable gain The analog gain-control input is scaled at 20 mV/dB and runs amplifier with linear-in-dB gain control for use from low from 50 mV to 950 mV. This corresponds to a gain of −2.5 dB frequencies up to several hundred megahertz. The range, to +42.5 dB, respectively, when the gain up mode is selected and flatness, and accuracy of the gain response are achieved using +42.5 dB to −2.5 dB, respectively, when gain down mode is Analog Devices’ X-AMP® architecture, the most recent in a selected. The gain down, or inverse, mode must be selected series of powerful proprietary concepts for variable gain when operating in AGC in which an integrated square-law applications, which far surpasses what can be achieved using detector with an internal setpoint is used to level the output to competing techniques. 354 mV rms, regardless of the crest factor of the output signal. A single external capacitor sets up the loop averaging time. The input is applied to a 9-stage, 200 Ω resistive ladder network. Each stage has 5 dB of loss, giving a total attenuation of 45 dB. The AD8367 can be powered on or off by a voltage applied to At maximum gain, the first tap is selected; at progressively the ENBL pin. When this voltage is at a logic LO, the total lower gains, the tap moves smoothly and continuously toward power dissipation drops to the milliwatt range. For a logic HI, higher attenuation values. The attenuator is followed by a the chip powers up rapidly to its normal quiescent current of 42.5 dB fixed gain feedback amplifier—essentially an 26 mA at 25°C. The AD8367 is available in a 14-lead TSSOP operational amplifier with a gain bandwidth product of package for the industrial temperature range of −40°C to +85°C. 100 GHz—and is very linear, even at high frequencies. The output third order intercept is +20 dBV at 100 MHz (+27 dBm, re 200 Ω), measured at an output level of 1 V p-p with VS = 5 V.
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Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION INPUT ATTENUATOR AND GAIN CONTROL INPUT AND OUTPUT INTERFACES POWER AND VOLTAGE METRICS NOISE AND DISTORTION OUTPUT CENTERING RMS DETECTION APPLICATIONS INPUT AND OUTPUT MATCHING VGA OPERATION MODULATED GAIN MODE AGC OPERATION MODIFYING THE AGC SETPOINT EVALUATION BOARD CHARACTERIZATION SETUP AND METHODS OUTLINE DIMENSIONS ORDERING GUIDE